Alkylsulfites and amino-substituted pyrazolones and process of making same.



UNITED STATES PATENT OFFICE.

max BOCKMUHL AND GUSTAV EBERT, or HooHsT-oN-THE-MAIN, GERMANY, ASSIGN:

one To FABBWERKE voma. mmsrnn LUCIUS & estimate, or HiDCHST ON-THE- mun, GERMANY, A CORPORATION oreERMANY.

ALKYLSULFITES OF AMINO-SUBSTITUTED PYRAZOLONES AND PROCESS OF MAKING Patented Mar. 25, 1913.

SAME.

1,056,881. Specification of Letters Patent.

No Drawing.

To all whom it may concern:

Be it known that we, Max Bocmn'inn, Ph. D., chemist, and GUSTAV Ennnr, Ph. D., chemist, citizens of the Em ire of Germany, residing at Hochst-on-the- Iain, Germany, have invented certain new and useful Improvements in Alkylsulfites of Amino-Substituted Pyrazolones and Processes of Making Same, of which the following is a specification.

\Ve have found that new substances of great therapeutic valve can be obtained by causing formaldehyde-bisulfite of the alkalimetals or ammonium to act upon aminosubstituted pyrazolones. In the place of the formaldehyde-bisulfite-alkali-metals or ammonium there may be used their homologues, such as the acetor propionaldehydebisulfite. The technical preparation of these bodies in a pure state involves some diiliculties. For instance if the solutions, obtained by heating i-antipyrylamin or its derivatives with a solution of formaldehydcbisulfite, are evaporated on the steam-bath while stirring, and the resultin mass is then dissolved in hot alcohol, the filtration of the turbid solutions thus obtained is, even when the filtration is effected in oacuo or by coinpressed air, so difiicult, owing to the fine subdivision of the particles of the separated bisulfite, that the substances crystallize while yet on the filter. Although the filtration is greatly improved by very slowly evaporatmg the liquids of the reaction, it appears that in this case the isolated bodies are not uniform, because they artly decompose when their solutions are lieated for a long time on the water-bath. Now we have made the observation that the products of the reaction can be very easily purified by allowing the liquids of the reaction, obtained by heating l-antipyrylamin or its derivatives with a solution of formaldehyde bisulfite, to stand in open, fiat basins at ordinary term perature, or at any temperature up to 0., either in the air or in 'vacuo, then dissolving in hot methyl alcohol the substances which have solidified after some time into crystal-cakes, evaporating the solutions, which can be easily filtered, and finally redissolvin the residues in alcohol. The alkylsulfites o the amino-substituted pyrazoloncs Application filed June 25, 1912.

Serial No. 705,799.

are obtained as white powders, readily soluble in water, but difiicultly soluble in benzene, acetone and ether.

Example I: 100 parts of 1-pheny1-2.3 dimethyl-4-amino-5-pyrazolone (4 antipyrylamin) are dissolved with aid of. heat in 37 parts of a solution of formaldehyde of 38% strength and 132 parts of sodium bisulfite of 39% strength, the solution is poured in flat basins and left to itself for some days at ordinary temperature or at any temperature up to 50 C. The solidified masses are then freed from the mother-liquor adhering to them by pressure or centrifuging, and dissolved, while hot, in methyl alcohol in the proportion of 1:15. The filtered solution is evaporated in 'vacuo until it crystallizes, and after cooling the separated product is filtered oil and again purified by dissolving 100 parts of the compound in 50 parts of hot water, adding 500 parts of hot alcohol (98%), and filtering on the product crystallizing out in the cold.

The compound thus obtained corresponds to the formula:

CoHl

I CO/N\N i=2 CH; Nil-ClXgOSOgN-D.

It sinters at 23l233 C. with decomposition; it dissolves in cold water in the proportion of 1:1, and is almost insoluble in the usual organic solvents except alcohol. The addition of barium chlorid and mercury chlorid gives rise to slight opalescence in its aqueous solution. The addition of silver nitrate does not at first cause the solution to change, but it soon becomes turbid and separates silver. The addition of a small quantity of ferric chlorid causes the solution to assume a dark color which disappears again after a short time; if an excess of ferric chlorid is added, it assumes a dark brown color which after some minutes turns cherry-red. \Vhcn diluted hydrochloric acid is added, the aqueous solution remains clear.

Example II: 10.7 parts of 1-p-tolyl-2.3.- dimethy -4-amino-5-pyrazolone (see German Patent 92OQ9) are heated for some time on the water-bath'with a solution of 3.7 parts of formaldehyde and 13.2 parts of sodiumbisulfite, and the product obtained is dried on a clay slab and then redissolved in chloroform. The substance, dried over sulfuric acid, commences to sinter at 120 C. and decomposes at 125 with-etfervescence. The com )ound is very readily soluble in water and also dissolves in hot alcohol and chloroform.

Example III: 12.2 parts of l-p-ethoxyhenyl 2.3 dimethyl 4. amino 5 -.pyrazoone are heated for some time on the waterbath with a solution of 3.7 parts of formal dehyde and 13.2 parts of sodium-bisullite, and then purified as indicated in Example II. The substance is dried over sulfuric acid, whereby the meltingand decomposition-point is raised, in consequence of the loss of water of crystallization (the melting point varying from 113-115 C.) It is readily soluble inwater and also in hot alcohol and chloroform. The 1-p-ethoxyphcnyl-28- dimethyl i-amino-5-pyrazolone, which serves as parentroduct, is obtained according to the metho usually employed for preparing the -i-aminoantipyrin, namely, by reducing the p-ethoxy-2.3-dimethylt-nitroso-5-pyrazolone obtained from p-etboxy-2.3-dimethyl- 5-pyrazolone treated with nitrite. Its melting point lies between 132133 C.

Example IV: 20 parts of l-p-aminophenyl-2-3-dimethyl-5-pyrazolone (see D. R. P. 92990) are dissolved, while hot, in 60 parts of water, mixed with 8 parts of technical formaldehyde and 28 parts of a solution of sodium-bisulfite, and allowed to stand over night. The mass is then evaporated on the water-bath until it assumes a syrupy consistency, the residue is dissolved in alcohol, and the filtered solution precipitated with acetone. The thus-produced sodium salt of the l-p-aminophenyl-2-3-dimethyl- 5-pyrazolone-methyl sulfite is hygrosco ie, readily soluble in water and methyl alco 101, more difiicultly soluble in ethyl alcohol, insoluble in ether and acetone.

Example V: A solution prepared by aid of heat with 22 parts of l-p-aminophenyl- 2.3.4-trimethyl-5-pyrazolone (D. R. P. 238250) in 100 arts of water, is mixed with 28 parts of a so ution of sodium-bisulfite and 8 parts of technical formaldehyde, allowed to stand over night, and then evaporated until it crystallizes. The sodium salt separated by filtration from the mother li uor, is obtained in a pure state by reerystal ization in alcolhol of 90% strength. It forms a crystalline powder which is, stable in the air, readily soluble in water and methyl alcohol, ditiicultly soluble in ethyl alcohol, and insoluble in ether and acetone.

Example VI: 10.7 parts of l-p-aminophenyl-BAA trimethyl-p razolone are digested on the water-bat with a solution about 9; hour.

consisting of 3.7 parts of dissolved formaldehyde and 13.2 parts of a technical solution of ,bisulfite, until the mass, at first solid and agglomerated, is dissolved, which takes The whole is allowed to stand on the steam bath for a short time longer and is then poured into a basin, in which it soon solidifies. After completely cooling, the mass is carefully separated by filtration from the adhering mother-liquor and dissolved in 1-5 times its quantity of cold methyl alcohol. The solution is clarified by filtration and evaporated, and the residue solidifying on cooling is redissolved from alcohol. The substance melts at 127 C. with decomposition. It very readily dissolves in water and methyl alcohol, more diilieultly in ethyl alcohol, scarcely in acetone, chloroform and ether.

Example VII: 10 r. of aminoantipyrin are heated for some time on the water-bath with a solution of 2.2 gr. of acetaldehyde and 13.2 gr. of a solution of sodium-bisulfite (of about 39%), and the resulting clear solution is left to itself. On the following day the crystalline magma is filtered off, the

residue dried upon a clay slab, and redissolved in alcohol. The substance dissolves very readily in water, readily in hot alcohol and methyl alcohol, more ditlicultly in chloroform. It is insoluble in ether, acetone and benzene, and has a melting point of l2%-l25 0.

Example VIII: 10 gr. of aminoantipyrin are dissolved by aid of heat in a solution of 2.9 gr. of proplonaldehyde and 13.2 gr. of a solution of sodium bisulfite, the further operations being carried out as indicated in vExample VII. The raw product is redissolved in absolute alcohol (1:2). The sub stance thus obtained melts not quite exactly between 124-125" C. At 130 C. decom o sition sets in. The compound is very rea ily soluble in water, and is also soluble in alcohol and hot chloroform.

In preparing the potassium and ammonium salts, the corresponding potassiumand ammonium-bisulfite, respectively, are substituted for the sodium bisultite, the further operations being as indicated in Examples 1-8 for the preparation of the sodium salt.

The pharmacological experiments with the new compounds showed that, even when administered in comparatively small doses, they are of a highly antipyretic and antineuralgic efficacy, without producing the slightest toxic symptoms. They act very rapidly and regularly, which is evidently due to their ready solu ility in water. Their action is more eliicacious than that of antipyrin, without being attended by undesirable secondary eifects, as is the latter.

The term alkali-metal bisulfite derivatives, used in claim 1,-is intended to inelude the corresponding ammonium, compounds.

Having now described our invention, what 3. As new articles of manufacture, the

alkyl-sulfites of the amino-substituted pyrazolones, being white owders readily soluble in water, difficult y soluble in benzene, acetone and ether, and possessing highlyantipyretic efiicacy.

4. As anew article of manufacture, the body of the formula:

being a white powder, readily soluble in water, diflicultly soluble in benzene, acetone and ether, and possessing highly-antipyretic efficacy.

In testimony whereof, we afiix our signatures in presence of two witnesses.

MAX BOCKMUHL. GUSTAV EBERT.

il-cn,

- \Vit-nesses:

J EAN GRUND, CARL GRUND.

Copies of, chi: patent may be obtained for five cents each, liy addressing the "Commissioner of Patents, Washington, D. 0. 

